It is known in the art to utilize trace or locator wires to mark the location of underground utility conveyances such as water pipes, gas lines, and the like. The purpose of such locator wires is to provide a way to locate buried utility conveyances, particularly in the case of non-electrically conductive utility conveyances, by detecting a signal passed through the locator wire. Current utility construction practices include placement of an insulated locator wire in a trench containing, for example, a water line or gas main. Commonly, non-electric grade insulated 12 gauge or 14 gauge wire is utilized. By connecting a signal generator such as a line location transmitting device to the locator wire, a line location receiver may detect the signal induced, allowing easy location of an underground system such as a water line or gas main from the surface without need for random digging. This method is utilized by many utility companies to facilitate construction and/or excavation activities, i.e. to allow construction and/or repair work without fear of rupturing existing water lines or gas mains.
A locator wire must be terminated in some fashion to reduce signal bleed or transfer. Current industry practices include connecting the locator wire to existing structures, such as, for example, fire hydrants or gate valves. Another common practice is to extend the locator wire above ground and directly attach it to a utility construction, for example a fire hydrant. Yet another currently employed practice is to connect the locator wire to a short section of electrical ground rod and embed the rod in a concrete pad.
Disadvantageously, all of the above methods allow some level of signal bleed and/or signal transfer from the locator wire to adjacent utility constructions. Such signal bleed and/or transfer can result in difficulty in locating the buried utility construction. It is known that any signal bleed or transfer at or near the point at which a line location transmitter is connected to the locator wire will greatly reduce the distance at which the induced signal can be detected. In addition, the practice of extending the bare locator wire above ground exposes the wire to damage from, e.g., use of the utility construction to which the wire is connected, from mowing operations, or the like, and reduces the effective life of the locator wire. The practice of attaching the wire to a section of electrical ground rod and embedding the rod in concrete is labor intensive in the installation, and also allows signal bleed or transfer. Such signal bleed/transfer at or near the point where the line location transmitting device is connected to the trace wire greatly reduces the distance at which the induced signal may be detected.
Accordingly, there is need in the art for methods for terminating locator wires to provide long-term usage with minimal loss of signal upon operation. The present invention satisfies this need in the art, advantageously providing methods for terminating locator or trace wires which electrically isolate the locator wire and minimize signal bleed or transfer, while requiring less labor for installation than current systems.